Field of the Invention
The present invention relates to wireless communication and, more particularly, to a method and apparatus for receiving data by a relay station in a backhaul link between a base station and the relay station in a wireless communication system.
Description of the Related Art
An ITU-R (International Telecommunication Union Radio communication sector) is working on standardization of IMT (International Mobile Telecommunication)-Advanced, a next-generation mobile communication system after the third generation. IMT-Advanced aims at supporting IP (Internet Protocol)-based multimedia service at a data rate of 1 Gbps in a stationary and low-speed movement state and at a data rate of 100 Mbps in a high speed movement state.
3GPP (3rd Generation Partnership Project) is preparing LTE (Long Term Evolution)-Advanced (LTE-A), an advanced version of LTE which is based on OFDMA (Orthogonal Frequency Division Multiple Access)/SC-FDMA (Single Carrier-Frequency Division Multiple Access) transmission scheme, as a system standard that meets the requirements of IMT-Advanced. LTE-A is one of potential candidates for IMT-Advanced. Primary techniques of LTE-A include a relay station technique.
A relay station (RS) is a device relaying signals between a base station (BS) and a user equipment (UE), which is used to extend a cell coverage and improve throughput of a wireless communication system.
Currently, research into a method for transmitting signals between a BS and an RS in a wireless communication system is actively ongoing in a wireless communication including the RS. The use of the related art method of transmitting signals between a BS and a UE as it is in order to transmit signals between a BS and an RS may be problematic. For example, in the conventional LTE, a BS transmits only resource block allocation information (or resource block assignment information) in a frequency domain with respect to a PDSCH (physical downlink shared channel), via which data is transmitted, through a PDCCH (physical downlink control channel), via which a control signal is transmitted, to the UE, and does not transmit allocation information regarding OFDM (orthogonal frequency division multiplexing) symbols in a time domain. This is because the UE can know about the allocation information regarding the OFDM symbols in the time domain with respect to the PDSCH from the size (the number of OFDM symbols) of the PDCCH transmitted via a PCFICH (Physical Control Format Indicator Channel).
In this respect, however, the backhaul link between the BS and the RS has the characteristics in which the OFDM symbols for the RS to receive the PDCCH thereby may differ according to the size of the PDCCH transmitted by the BS to the UE and the size of the PDCCH transmitted by the RS to the UE connected to the RS. Thus, in the related art, the RS may not properly receive the PDCCH from the BS, and resultantly, the RS cannot properly receive data.
A method and apparatus for receiving data by a RS in consideration of the characteristics of the backhaul link in the wireless communication system including an RS are required.